Shock sensors employing reed switches have been used in motor vehicles to detect a vehicle collision. When a collision occurs, the shock sensor triggers an electrical circuit for the actuation of safety devices such as inflating air bags, tensioning seat belts, and other similar systems. Such shock sensors typically employ a reed switch and an acceleration sensing magnet which is typically biased by a spring away from the central activation region of the reed switch, such that the reed switch is open when the shock sensor is not subject to acceleration. When the vehicle and the shock sensor, which is attached to the vehicle, are subjected to a crash-induced acceleration, the magnet, acting as an acceleration-sensing mass, moves relative to the central activation region so exposing the overlapping reeds to a magnetic field, causing them to mutually attract and close the reed switch.
Known shock sensors employing reed switches are typically considerably larger than the reed switch contained therein because of the necessity of packaging the activation magnet around or adjacent to the central activation region of the reed switch.
Because placement of the shock sensor within the automobile may be critical to its reliable and effective operation, packaging size of the overall shock sensor is important, in that a smaller sensor may be more readily placed in an effective location. Other known shock sensors have insufficient dwell times, especially in minimum crash situations, where the dwell time of the sensor may be zero.
What is needed is a shock sensor with extended dwell and extended minimum dwell, which is available in a physical package of smaller dimensions.